646310551 has 2 divisors, whose sum is σ = 646310552. Its totient is φ = 646310550.

The previous prime is 646310543. The next prime is 646310563. The reversal of 646310551 is 155013646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646310551 - 2³ = 646310543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646310591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323155275 + 323155276.

It is an arithmetic number, because the mean of its divisors is an integer number (323155276).

Almost surely, 2^646310551 is an apocalyptic number.

646310551 is a deficient number, since it is larger than the sum of its proper divisors (1).

646310551 is an equidigital number, since it uses as much as digits as its factorization.

646310551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 646310551 is about 25422.6385530692. The cubic root of 646310551 is about 864.5970484437.

The spelling of 646310551 in words is "six hundred forty-six million, three hundred ten thousand, five hundred fifty-one".